homeostasis Flashcards
what is homeostasis
to keep a stable environment (conditions) despite a fluctuating outer environment
negative feedback (homeostasis)
keeping conditions constant (ex. body temp)
positive feedback
amplifying (ex. giving birth)
what are the two parts of the central nervous system
brain: hind, mid, fron
spinal cord (connected to the hind brain)
where are reflexes received
interneuron (in the spine)
explain how action potential in generated?
what are the parts of a neuron (diagram)
soma (cell body)
axon
pre synaptic membrane (releases neurotransmitters)
- neurotransmitters: diffuse across the synaptic cleft to inhibit or pass forward a signal
synapsis: 2 proximal neurons
dendrites: receiving ends of information
myelin sheath (produced by schwann cells)
nodes of Ranvier: enable saltation of the action potenial
how does the hypothalamus link the nervous and endocrine systems
how do lipid and protein based hormones control transcription?
lipid: pass directly into cells, bind to DNA and act as transcription factors
protein: use a process called transduction, exert influence indirectly
(cascade of chemical reactions including cAMP)
what kind of hormones does the pituitary gland secrete? what are the names and functions of these hormones
tropic hormones (control other endocrine glands)
hGH: human growth hormone
tsh: thyroid stimulating hormone
LH: luteinizing hormone
FSH: follicle stimulating hormone
prolactin: stimulates milk production
ADH: water retention in kidneys (antidiuretic hormone)
oxytocin: stimulates uterine contractions and release of milk by mammary glands
ACTH: stimulates adrenal cortex to secreate glucocorticoids
what do the thyroid and parathyroid glands do?
thyroxine (t4, t3): metabolism
calcitonin: lowers blood calcium
PTH: raises blood calcium
(together they control blood calcium levels)
what gland secretes melatonin?
pineal gland
what does the pancreas do and how?
controls blood sugar levels by secreting insulin (to lower) and glucagon to raise
insulin: secreted by beta cells
glucagon: secreted by alpha cells
what is secreted by the adrenal gland?
adrenal cortex:
- glucacorticods: tissue to raise blood glucose and break down proteins
- mineralcorticods: absorption of Na+ and water by kidneys
- gonadacorticods: secondary sex characteristics
- epinephrine: fight or flight
what does the thymus do and where is it located?
thymosim: development of T-cells for immune response
in the chest, between the lungs and behind the breastbone or sternum
how do secondary sex characteristics develop in males vs females, what glands help with this?
the hypothalamus secretes GnRH which stimulates the secretion of LH and FSH by the pituitary gland. this activates, in males, the testes and in females the ovaries. estrogen are secreted by the ovaries and testosterone by the testes for secondary sex characteristics.
*the female reproductive system is a little more complicated than this**
what is the uterine cycle responsible for?
synchronizing the development of the endometrium (uterine lining) with ovulation
what are the stages of the ovarian cycle
follicular (follicle/support system to the egg + egg) and luteal (corpus luteum)
label the female and male reproductive systems
what does the frontal lobe do
voluntary control and movement such as organizing, initiating and reaching a goal
what does the temporal lobe do
manages emotions, processes info from senses, understanding languages, memories
what does the medulla oblongata/hindbrain do?
maintains homeostasis, reflexes automatic body responses like heart rate, constriction and dialation of blood vessels, deep breathing, swallowing, coughing
what does the cerebellum do?
unconscious movement such as posture, reflezes, body movements. also voluntary motor skills
what does the occipital lobe do?
visual processing and perception such colour, form, motion
what does pons do?
serves as a relay centre between brain and spinal cord as well as the left and right of the cerebrum and cerebellum
what does the thalamus do?
processes all body senses (except smell) and relays info between hind and fore brain
what does the corpus callosum do?
white matter in the centre of the brain, sends messages between 2 distinct hemispheres of the brain
what does the midbrain do?
processes visual and auditory info between hind and forebrain. relays info from sensory neurons
what is the role of parietal lobe?
processes all sensory input such as touch and temperature
what do osmoconformers
they go with the flow of the environment instead of adjusting internal environment
name the 4 types of excretory systems and what organisms they are in
flatworms: protonephridia
annelid: metanephridia
insect: malpighian tubules
mammae: nephron
how do animals in aqueous environments get rid of toxic waste
NH3 (ammonia) goes directly into the environment (ex. fish: gills)
what happens if the osmolarity it too high in the collecting duct
ADH from hypothalamus is secreted, making collecting duct more permeable to water and lowering osmolarity
label the nephron diagram and explain
what are the two kinds of motor pathways?
autonomic nervous system (NOT under conscious control)
somatic nervous system (under conscious control)
Explain the stress response
Stress, hypothalamus, nerve impulses, spinal cord, sympathetic nervous system, adrenal medulla (epinephrine, norepinephrine)…anterior pituitary secretes ACTH, adrenal cortex (glucocorticoids - cortisol, mineralcorticods - aldosterone, raises blood pressure )
Short term:
Long term:
Cortisol?
Glucocorticoid secreted by the adrenal cortex.
Works with the epinephrine in the stress response (but it’s longer lasting)
Primarily raises blood glucose by breaking down muscle proteins and releasing the AA into the blood. The liver then makes glucose with these AA.
cortisol also attacks fat cells to release/break down into glucose
Natural anti inflammatory that suppresses the actions of the immune system
Too much cortisol can impair thinking, damage heart, high blood pressure, lead to diabetes, increase infection (cuz surprises immune system)
Label the nephron and explain what it does
